Stoker



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Apri15,1927. l 1,623,424

' l E. LUNDGREN STOKER Filed May' 4. 192s e sheets-sheet 6 @Kfm/Emma www4 5 ATTORNEYS.

Patented Apr. `5, 1927.

UNITED STATES PATENT OFFICE.

'EDWIN LUNDGREN, OF FREDERICK, MARYLAND, ASSIGNOR TO lCOMBUSTION ENGI- NEERING CORPORATION.. OF NEW YORK, N, Y., A CORPORATION OF NEW YORK.

STOKER.

Application led May 4, 1923. Serial No. 636,523.

My invention relates to improvements in underfeed stokers and is particularly applicable to inclined underfeed stokers of the multiple retort type. The principal object of my invention is to provide a retort underfeed Stoker having an increased fuel burning capacity per retort. It further has for its object to provide a Stoker in which substantially the entire retort area is utilized as an active grate surface.' 1t further has for its object to provide such a Stoker having a fuel support which is practically 100% effective grate surface. A further object f the invention is to utilize the secondary fuel feeding ram as an active grate surface, admitting air into thefuel bed. A further object is to provide an active grate surface between the grate surfaces adjoining the retort having the feature of being supplied with a separately controlled amount of air. A further object of my invention is to provide means by which the air passing through the rams and through the stationary tuyres respectively' can be independent] controlled so that the air passing throug i either or both of those two kinds of frate surfaces can be independently throttled or cut oit'. A further object is to provide a Stoker of the type mentioned with a variable active fuel burning surface in order to vary the fuel burning efficiency as desired. A further 'object is to provide a retort stoker having a ram producing a. no vel forward and lateral fuel feeding action.

It is well known that stokers of the inclined multi-retort type, generally stated, have their best fuel burning efficiency when the average fuel being burned is 30 to 40 pounds of coal per square foot of grate surface, and that when operated at higher combustion rates the combustion efficiency decreases rapidly, requiring relatively high air pressure for the combustion of the fuel. By means of the improved form of Stoker herein shown and described, the secondary fuel feeding rams can be utilized either as a feeding means only, producing a relatively low combustion rate, or can be converted into active grate surfaces supplying air to the superimposed fuel Vso as to secure with the same air pressure/higher combustion rates equal to those secured b v the use of a larger Stoker, making it unnecessary to install a larger stoker in order to obtain the higher combustion efliciency corresponding to the most economical combustion rate.

The following is a description of an em.

bodiment of my invention, reference being had to the accompanying drawings, in which,

Figure 1 shows a plan view'of a portion pf a Stoker furnace embodying my invenlon;

Fig. 2 is a transverse section of the same on the line 2 2, Fig. 1;

Fig. 3 is a sectional view of parts Showing one of the stationary tuyres with its air controlling damper;

Fig. 4 is an enlarged view of the pusher Within one of the retorts, intermediate portions being broken away;

Fig. 5 is a section on the line 5 5, Fig. 4;

Fig. 6 is a section on the line 6-l6, Fig. 4;

Fig. 7 is a section on the line 7-7, Fig. 4;

Fig. 8 is a detail plan view of the4 top member of the pusher; Fig. 9 is a side elevation of the saine; Fig. 10 is a section on theline 10-10,*Fig. 8. i

7F ig. 11 is a bottom plan View; Fig. 12 is a section on the line 1%12, Fig. 8; v lTFig. 13 is a section on the line 13s-13,

ig. 14 is a section on the line lll- 14, Fig. l0;

Fig. 15 is a detail plan View of the lowermost member of the pusher;

Fig. 16 is a section on the Fig. 15;

Fig. 17 is a bottom plan view; beFig. 18 is an end elevation of said mem- Fig. 19 is a detail plan View of one of the similar intermediate sections;

Fig. 20 is a side elevation of the same; l

Fig. 21 vis a section on the line 21-21 Fig. 19;

Fig. 22 is a. bottom plan view;

Fig. 23 is a section on the line 223-23, Fig. 19; and

Fig. 24 is a section on the line`24-24, Fig. 19.

Referring more particularly to the drawings, 2-2-2 are inclined series of stationary tuyres-alternating with retorts 4, each of which retorts is supplied with fuel from a hopper 6 by means of main plungers 8 line 1er-1e,

v formed on the` flanges 23 and secured in ad-V in the ordinary underfeed manner, the stationary tuyres having the usual discharge openings 3. 10 and 12 are the usual dump grates located at the lower end of the inclined series of stationary tuyres. and adapted to discharge refuse into the ash pit 14. Extending below the retorts 4 and the stationary tuyres 2 is a4 chamber 16 supplied with air from a duct 18, the sup'plly being controlled by the damper 20. ie retorts 4 are each provided with a bottom plateI 22 on which slides an auxiliary pusher consisting of a base plate 24 which'is secured to an under plate 26 to which is piv-l otally connected a rod 28' which in turn is connected to a sliding rod 30 having spaced abutments 32 and 34 which' are alternately engaged by a' projection 36 upon a slide 38 supported by the guide-rod 4() and connected so as to move with the plunger '8, except for the lost motion between the projections 36 and the abutments 32 and 34, thus causing the base plate 24 to reciprocate within the retort 4. The parts mentioned, except `the auxiliary pusher hereinafterl to be described Ain detail, are similar to arrangements v heretofore used and familiar to those skilled in the art. v Upon the .base plate 24 are mounted upper and lower pusher members 42 and 44, between which is mounted. a series of tuyre blocks 46 'similar to one another and constituting intermediate pushing members. The lower member 44 is secured 'to the base plate by a bolt 48 and a projection 49 which vtially upon the lower pushing member 44,

being provided with a rearwardly and Adownwardly extending tongue 50 which hooks beneath the upper edge of the member 44. The succeedingr intermediate members are similarly related to the precedingv intermediate members and are secured thereto in a similar manner. The up r pusher mem ber 42 rests partially upon t e u permost intermediate member and partial y upon the hase plate 24 and is secured to 'the base plate by a bolt 52 so that the upper and lower ppsher members and the intermediate memrs are all fixed in relation to one another and to the base plate. The base plate is held down upon the bottom plate 22 by the under plate 26. to which it is bolted so as to be free to slide upon the base plate. The plate 22` is provided with depending strengthenin flanges 23 and is secured in position by lts 54 and 56 whichvhold it against flanges 57 on the side walls ofthe retort.

The plate 22 has openings 58 and 60, which can bewholly or partially closed by sliding dampers 61 resting on ledges 62 ber 44 has in its forward end a series lof bot-- tom grooves forming air ports 66 'througlh which part of this air is discharged to t e fuel in advance thereof. Each of the intermediate members has on its bottom faces grooves 68 through which the air supplied to their under sides to the ports 64 is discharged. The upper member 42 is provided on its under face with similar air discharge ports. lskeleton form so as to form in conjunction with the upper and lower members an air chamber into which the ports 64 of the base plate open. to admit air subject to the control of the dampers 61.-

vThe auxiliary pusher 'thus constructed is reciprocated to feed the fuel through the retort in which it is located, and, on account of its grate-like construction,constitutes an actire grate surface on which the overlying fuel is burned. thus serving not only to move the fuel through the respective retorts but also serving as an air-supply grate, with the result that the effective grate area of the stoker is increased and corresponds to substantially per cent of the fuel supporting surface of the Stoker, resulting in an increased capacity of the Stoker and permitting a higher rate of combustion than has heretofore been attained instokers of the multi-retort type. f'

' The feeding surfaces of the rams are ar- The intermediate members are of' rangedto give a relatively` large pushing surface at the lower ends'of the rams in order 'to obtain a positive feeding effect of the fuel' bed at the low'er part of the retorts.V

The uppermost grate units preferably have smaller feeding lsurfaces as the feeding effect upon the fuel bed at the upper portion of the ram is greatly controlled by the main feeding ram of the stoker. The upper portion of the auxiliary pusher. projects so as to provide a greater agitating surface than the agitating surfaces of the intermediate units, since the fuel bed requires considerable a itation at the upper end of theretort ue to the thick fuel bed at this point. The norllnal outline of the fuel bed for best operation is shown in dots by the line 20. The upper and intermediate members 42 and 46 of the pushers are moreover tapered rear wardly so as to act as plows tendi-n -to shove the Ifuel laterally toward the vxed tuyres and in order to give the fuel a shove in an upwardly inclined direction the pushing faces 42 and` 46 .are in addition somelsvhat rounded as shown more particularly in Fig. 4 so that they `not only have a forward propelling action and a lateral propelling action but also .have an upwardly inclined propelling action, resulting in an even dislltl iso

engage pinions 74 mounted upon a transversely extending shaft 76 so that they can be moved Whenever` desired to throttle the air passing to the stationary tuyres. In this Way the air in passing to the stationary tuyres can be controlled' independently1 of the air passing through the movable rams into the retorts. Since theamount of air passing through the rams can also be adjusted by the means heretofore described, the air 'supply to all portions of the effective grate surface can be adjusted to meet vary ing conditions. The means for adjusting and securing the damper; 61 controlling the air supply qto the ports in the auxiliary pushers do not have to be ladjustable by means extending outside of the furnace, since these adjustments ordinarilyv are necessarv only when a change in the nature of the fuel used 1s made and when once adjusted so as to meet that condition should not require further adjustment during the ordinary run ning of the furnace. It is to be noted that the two dampers for controlling the air to each auxiliary pusher are independent of one another andtherefore can be independently adjusted so as to control the airedmitted to different arts of each pusher as well as to shut it oilpaltogethcr.r

The main rams underfeed to .the retorts the fuel received from the hopper, which, when it .reaches the auxiliary pushers, fed by those pushers .'o as to be supplied to the stationary tuyres. The fuelris fed tothe stationary tuyres in an ignited `condition having become quickly ignited as soon as exposed tothe heated atmosphere ,of thefurnace on account of the oxygen-being ysup.`

plied to it. The action of the Stoker so far as the stationary tuyres is concerned v,is underfeed while the action so far' as feeding the fuel along -the ,grate surfaces of the auxil' iary rams is concerned isoverfeed so that the fuel which is belngxconsume'd 1s partly underfed and partly overfed as contrasted with the multiple -retort Stoker heretofore used in which the fuel fed to activel grate surfaces was always underfed.-

As Willbe evident to those 'skilled in the artmy invention permits of various m`odi ications without departing from the spirit thereofv or the scope of the appended claims.

What I claim is:

l. In a multiple retort Stoker, the com-V bination of a plurality of retorts, means for underfeedingfuel to said retorts, an overfeed gate surfacel within each of said retorts and extending throughout the major portion thereof, means for supplying air to said'loverfecd grate surface, andmeans for "controlling the supply of air to one longitudinally extending part of said overfecd grate surface independently of another such part of said surface. v

2, A stokerhaving, in combination, a retort having. a bottom wall having an openingr therein, afuel pusher having a base of hollow constructionv mounted to slide on said bottom 'wall over said opening and having its interior in communication therewith, and tuyre structures removably.mounted on said base and having tn vre openngs'therei-n in communication wifh the interior of said base.

3. 'A Stoker having. in combination, a retort having a bottom ivall having an opening therein, a fuel pusher having a base of hollo construction mounted to slide on said bottom Wall overs-aid opening and having is interior in comnmnication therewith. and tuyre.,structures removably mounted on said hase, in interlocking engagement with each other and having tuyere openings in communication with the interior of said base.

4:. A stokerhn'ing, in combinaliom'a retort having a bottom u'allhaving an opening therein, a fuel pusher having a base of hollow construction mounted to slide on Asaid bottom Wall over said opening and having its interior in con'nnunication thcrewitlnand tuyre structures removably niouned on .said base., having` a tongue and slot connection between them and having tuyre openings in communication with the interior of said base.

5. A VStoker having, in combination, `a re'- tort having a bottom wall having an opening therein, a fuel pusher having a base of hollow construction mounted to slide on said .bottoni Wall over said opening and having its interior in communicationtherewitlnand tuyre structures removably mounted on said base and arranged one above the other in overlapping relation so as 4to form a series ot' pushing faces.

6. A multiple retort Stoker having, in combination. aplurality of retorts arranged side by side and spaced apart, tufvre structures` extending between thel adjacent side walls lof adjacent retorts, a wind box, arranged beneath the retorts and tuyre structures, an overfeed grate. surface 'within each retort, and independently controllable means for admitting air from said Wind box to said overfeed grate'surface and said rows of tuyre structures.A

7. A stoker having, in combination, a plurality of re'orts arranged side by side and spaced apart .,tuyre structures extending between the adjacent si'de- Walls of adjacent rctorts, a Wind box arranged beneath the retorts and tuyresructures, a fuel pusher mounted in each retort of hollow construction and having openings therein for admitting air to the fuel'within the retort, and

Vcontrolhible meansfor admitting airfrom 9. A Stoker havingrin combinatioma retort` a fuel pusher extending longitudinally of the retort of hollow construction 4and'hai-Y- ing a plurality'of openings for admittingair;

to the fuel Within the retort, means for supplying airto the'interiorv of the fuel pusher, and meansfor controlling the supply of Aair to one longitudinally extending part of the interior of said pusher independently of another such: part of said pusher. Y

10. A Stoker having, in combination, a 'retort having side walls and a bottom Wall.r` a row of-tuyere structures mounted uponthe v upper edgefof ,eacl'i of saidv side Walls, a fuelpusher comprising-a vbase mounted to slide i said bottom wall, andv^ 'upon' said base vinoverla'pping relation top provide a series .of

loneitudinally .onf tuye1e`-blocks mounted pushing faces arranged one behind thcother and to supplxy air to the fuel nuthin-the retort, said tuyeregblocls eXtendingy above .the lower edges of said rows of 'tuyre structures but spaced belowthe topsurfacesthereof,

said bottom wall-and base havingopenings for supplying air .to vsaid tuyre blo`cks',.and meansfor reciprocatingl said pusher longitudinally.v

11. A Stoker having, in combination, a retort having;r a bottom wall inclinedvdolwnwardly and rearwardly, a' fuel pusher havingv a base mounted to slide longitudinallyV on Sald bottom wall and extendingfrom,

near the upper end of said .bottom-'Wall Vto near the lovver'endthereof, and .tn vre bloclks mounted on said 'base `in overlapping relation to provide a series of pushing. faces arranged one behind the other, saidftuyre tudinally.y

blocks extending substantially from end to 'end of saidbase and `of substantiallythe width of the interior of'ztheretort, and said.

bottomwall .and r base. having' openings for supplying .;ir to-Qsaid. tuyre blocks, and

means for'rcciprocating `said pusher longi- 12. A ,stoker having, in combination, a retort having sidewalls and a bottom vvall inclined downwardlyand rearwardly and extending between the side walls, a row of- 'means for tuyre structures mounted upon the up er edge ofeach of said side Walls, a fuel 'pus er having av base mounted to slide longitudinally on said bottom Wall, and tuyre blocks mounted on said base and arranged to support and to supply air to the transverse centralportion of the fuel Within the retort, andsaid bottom wall andbase having open- Iings for supplyingr air to said tuyre blocks,

and. means `for reciprocating said pusher;

13.V A stokcrhaving' in combination, a retort having: a bottom Wall' inclined down-v ivardly'and ,rearwardly 'a fuel vpusher having a base mounted to slide longitudinally on said-bottoni Wall-having its topfsurface arranged substantially parallel with said bottom wall, and :tn vre blocksmounted.

upon thetopsurface-inf said basein overlappini; relation for suppl vlinv'gfffairv tothe]l fuel avithrn the retort` and 'for lproviding a series o't' pushing faces arrangedone gbehind.' the vother for .feeding .fn'ell'yjdoivny the retort dur- 1ng r thel reeiprocation `'ofthe pusher, said bottom wall. and said base-having 'openings1 for .supplying air-to saldftuyreblocks, and

means forrcciproc'ating said" pusher vlongi- I .tudinallyl Y 1 4. A stok'er having, inv combination, a re- ;tort Ahaving a .bottom.-wallinchned downwardly and rearwardly, a fuelpuslier having abasc mounted to slide longitudinally' on said-bottom -wall having its topsurface arranged substantially parallel with'said botvv'toin'WalL and tn vre blocks mounted upon thegtopsurface of said bassin overlapping relation for supplying air to the fuel lWithin .the retort and for 'providing a series of push- -ing faces arranged one behindthe other for feedii'ig'; the fuel downthe retort during the reciprocation of `the pusher, the overlapping surfacepmtions'v of said blocks being arranged substantially7 horizontal, and said bottom ivalljandA said base having openings for supplyingf'air to said tuyre blocks, and

v`means forfreciprocating said 'pusher longitudinally. f i.

. 15. A stokerghaving, in combination, a rel ltort having/side' walls and a bottom wall in.-

clined',downiv'a'rdly?and rearwardly and extendingbetween-A theside walls, a row of tuyre structures mounted upon the up er edge lof "eachv ofv said side walls, a fuel pusher 'having agpoiti'on of itstop surface provided with.tuyreop'enings and arranged to support andtofsupply airto the lcentral and vlower portion'sfof ,the fuel Within vthe retort andprovided witha plurality of steps formingfuel pushingjfaces extending above the lower edges of saidfrows oftuyre structures but spaced v below l,the top surfaces of thev tuyrestructures, means for supplying air to said tuyere 'openings m the pusher, and

vreclpricatlng; said pusher longitudinally. f EDWIN LUNDGREN: 

